Guinea pig 5-HT transporter: cloning, expression, distribution, and function in intestinal sensory reception
Guinea pig 5-HT transporter: cloning, expression, distribution, and function in intestinal sensory reception
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DOI：
10.1152/ajpgi.1998.275.3.g433
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发表时间：
1998-09-01
影响因子：
4.5
通讯作者：
Gershon, MD
中科院分区：
文献类型：
--
作者：
Chen, JX;Pan, H;Gershon, MD
对豚鼠小肠的研究表明，5-羟色胺（5-HT）可能是刺激感觉神经并引发蠕动和分泌反射的粘膜递质。我们验证了豚鼠绒毛上皮细胞能够灭活5-HT的假设，因为它们表达与5-羟色胺能神经元相同的5-HT转运体。从豚鼠肠黏膜中克隆出全长cDNA，编码一个630个氨基酸的蛋白，与大鼠和人5-HT转运蛋白的同源性分别为89.2%和90%。证明该cDNA编码豚鼠5-HT转运体的证据包括：1)在豚鼠脑干和粘膜的Northern印迹中与单一种mRNA（类似3.7 kb）杂交；2)转染的HeLa细胞通过饱和、高亲和力(Michaelis常数618 nM，最大速度2.4 × 10（-17) mol.cell(-1)）摄取[H-3]5-HT。min(-1))，氯丙帕明>丙帕明>氟西汀>地西帕明>齐美利定抑制Na+依赖机制。用原位杂交和免疫细胞化学方法证实了5-HT转运体在豚鼠大鼠小肠神经元和整个隐绒毛轴上皮中的表达。抑制粘膜5-HT摄取增强了粘膜下神经元对粘膜刺激的反应。因此上皮细胞对5-HT的再摄取似乎是终止5-HT的粘膜作用的原因。
Studies of the guinea pig small intestine have suggested that serotonin (5-HT) may be a mucosal transmitter that stimulates sensory nerves and initiates peristaltic and secretory reflexes. We tested the hypothesis that guinea pig villus epithelial cells are able to inactivate 5-HT because they express the same 5-HT transporter as serotonergic neurons. A full-length cDNA, encoding a 630-amino acid protein (89.2% and 90% identical, respectively, to the rat and human 5-HT transporters) was cloned from the guinea pig intestinal mucosa. Evidence demonstrating that this cDNA encodes the guinea pig 5-HT transporter included 1) hybridization with a single species of mRNA (similar to 3.7 kb) in Northern blots of the guinea pig brain stem and mucosa and 2) uptake of [H-3]5-HT by transfected HeLa cells via a saturable, high-affinity (Michaelis constant 618 nM, maximum velocity 2.4 x 10(-17) mol.cell(-1).min(-1)), Na+-dependent mechanism that was inhibited by chlorimipramine > imipramine > fluoxetine > desipramine > zimelidine. Expression of the 5-HT transporter in guinea pig raphe and enteric neurons and the epithelium of the entire crypt-villus axis was demonstrated by in situ hybridization and immunocytochemistry. Inhibition of mucosal 5-HT uptake potentiates responses of submucosal neurons to mucosal stimulation. The epithelial reuptake of 5-HT thus appears to be responsible for terminating mucosal actions of 5-HT.